Compression fittings are commonly used in the electrical industry for connecting conduit or tubing to bulkheads, panels, and junction boxes. The compression fitting used for this purpose typically includes a split ring. The split ring typically surrounds the conduit or tubing and seats on the compression ring and, as the compression nut is tightened, the two portions of the split ring are forced together by the force of the tightening compression nut against the split ring and the compression ring. In an ideal installation, the split ring is forced fully closed and the two surfaces of the split ring join together forcefully enough to create a rain tight fit.
Unfortunately, compression fittings of the type including a split ring very rarely form a rain tight fit on rigid conduit. The reasons for this are simple. Conduit, whether EMT (electrical metallic tubing) or plastic conduit, rarely has a perfectly formed outer surface as called for by industry specifications. EMT for example, often includes a weld seam that runs longitudinally along the outer surface of the conduit and is a byproduct of the manufacturing process. If a weld seam exists on the outer surface, a compression fitting using a split ring will not obtain a rain tight fit. Other flaws are typically found in electrical conduit, including out-of-roundness and tolerances that are out of specification.
As a result of the typical non uniformities encountered in commercially available electrical conduit, compression fittings employing split rings seldom obtain a rain tight fitting as claimed by the fitting manufacturer.
It is therefore an object of this invention to provide a compression fitting that is capable of obtaining a rain tight fit on all types of commercially available conduit, which typically may be out of round or include surface irregularities such as extending weld seams.